$-5qr - r + 7s - 5 = 9r - 3s + 4$ Solve for $q$.
Explanation: Combine constant terms on the right. $-5qr - r + 7s - {5} = 9r - 3s + {4}$ $-5qr - r + 7s = 9r - 3s + {9}$ Combine $s$ terms on the right. $-5qr - r + {7s} = 9r - {3s} + 9$ $-5qr - r = 9r - {10s} + 9$ Combine $r$ terms on the right. $-5qr - {r} = {9r} - 10s + 9$ $-5qr = {10r} - 10s + 9$ Isolate $q$ $-{5}q{r} = 10r - 10s + 9$ $q = \dfrac{ 10r - 10s + 9 }{ -{5r} }$ Swap the signs so the denominator isn't negative. $q = \dfrac{ -{10}r + {10}s - {9} }{ {5r} }$